Net Carb Calculator
Enter the nutrition label numbers to find the real net carbs per serving.
Formula: Total Carbs − Fiber − Sugar Alcohols. Most low-carb bread brands use erythritol or allulose, which have virtually no effect on blood sugar — subtract those grams in full. One exception: if the ingredients list maltitol (common in sugar-free candy and some bars), it does raise blood sugar meaningfully, so enter only half the sugar alcohol grams above. If you’re diabetic, confirm how your body responds to specific sweeteners with your care team.
Why Net Carbs Aren’t the Same as Total Carbs
“Net carbs” is a shorthand the low-carb community uses to estimate the carbohydrate grams that actually affect blood sugar. The idea: fiber and most sugar alcohols pass through your digestive system largely undigested, so subtracting them from total carbs gives a more useful number than the total carb figure alone.
It isn’t a perfect science — individual digestion varies, and some sweeteners (maltitol especially) affect blood sugar more than others. But for day-to-day meal planning, it’s the number most keto and low-carb trackers use. For the full breakdown of the formula and how different sweeteners behave, see our guide on what net carbs actually are.
Common Questions
Do all sugar alcohols count the same way?
No. Erythritol and allulose have almost no impact on blood sugar, so subtracting them in full is reasonable. Maltitol is the exception — it behaves closer to real sugar, so we recommend only subtracting half its grams (or none, if you’re diabetic and haven’t tested your own response).
Is the net carb formula accurate for diabetics?
It’s a helpful estimate, not a guarantee. Individual glycemic response varies, especially with modified wheat starch and certain fibers. If you’re managing diabetes, pair this calculator with your own glucose readings and check with your care team before making it your primary tracking method.
Where do I find these numbers on a nutrition label?
Total Carbohydrate, Dietary Fiber, and (if present) Sugar Alcohol all appear on the Nutrition Facts panel, usually indented under “Total Carbohydrate.” Servings per container is listed at the very top of the label.
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